Question

17. Nils swam a total of 6.48 km in three days. He swam 0.720 km longer on Day 2 than on Day 1. The distance he swam on Day 3 was 3 times the distance he swam on Day 2. How many kilometers did he swim on Day 3?

Answer 1

Let x = Day 1
Day 2 = x + 0.72
Day 3 = (x + 0.72)(3)
Total km = 6.48 km
6.48 = x + (x + 0.72) + ((x + 0.72)(3))
6.48 = x + x + 0.72 + 3x + 2.16
6.48 - 2.16 - 0.72 = 5x
5x = 3.6
x = 0.72
Day 3:
(x + 0.72)(3)
(0.72 + 0.72)(3)
(1.44)(3)
4.32
Nils swam 4.32 km on Day 3.

Answer 2

21.6 km

Explanation:

distance swam on day 2: 6.48+0.720 = 7.2 km

distance swam on day 3: 7.2*3 = 21.6 km